Hello,
On 22/10/13 - 21:38:10, Eric W. Biederman wrote:
> David Miller <da...@davemloft.net> writes:
> > From: fengguang...@intel.com
> > Date: Tue, 22 Oct 2013 22:41:29 +0100
> >
> >> We noticed big netperf throughput regressions
> >>
> >> a4fe34bf902b8f709c63 2e685cad57906e19add7
> >> ------------------------ ------------------------
> >> 707.40 -40.7% 419.60
> >> lkp-nex04/micro/netperf/120s-200%-TCP_STREAM
> >> 2775.60 -23.7% 2116.40
> >> lkp-sb03/micro/netperf/120s-200%-TCP_STREAM
> >> 3483.00 -27.2% 2536.00 TOTAL
> >> netperf.Throughput_Mbps
> >>
> >> and bisected it to
> >>
> >> commit 2e685cad57906e19add7189b5ff49dfb6aaa21d3
> >> Author: Eric W. Biederman <ebied...@xmission.com>
> >> Date: Sat Oct 19 16:26:19 2013 -0700
> >>
> >> tcp_memcontrol: Kill struct tcp_memcontrol
> >
> > Eric please look into this, I'd rather have a fix to apply than revert your
> > work.
>
> Will do I expect some ordering changed, and that changed the cache line
> behavior.
may it be the below?
Cheers,
Christoph
----
From: Christoph Paasch <christoph.paa...@uclouvain.be>
Subject: [PATCH] Fix: Dereference pointer-value of sk_prot->memory_pressure
2e685cad57 (tcp_memcontrol: Kill struct tcp_memcontrol) falsly modified
the access to memory_pressure of sk->sk_prot->memory_pressure. The patch
did modify the memory_pressure-field of struct cg_proto, but not the one
of struct proto.
So, the access to sk_prot->memory_pressure should not be changed.
Reported-by: Fengguang Wu <fengguang...@intel.com>
Signed-off-by: Christoph Paasch <christoph.paa...@uclouvain.be>
---
include/net/sock.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/net/sock.h b/include/net/sock.h
index c93542f..e3a18ff 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1137,7 +1137,7 @@ static inline bool sk_under_memory_pressure(const struct
sock *sk)
if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
return !!sk->sk_cgrp->memory_pressure;
- return !!sk->sk_prot->memory_pressure;
+ return !!*sk->sk_prot->memory_pressure;
}
static inline void sk_leave_memory_pressure(struct sock *sk)
--
1.8.3.2
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
